An accurate inspection of the ZFC curve, Fig. REF (b), reveals the presence of two anomalies at \(T_C\)  = 112 K and \(T^{*}\)  = 85 K, and distinct scenarios can be drawn to explain it. The second anomaly could be related to another magnetic transition apart from \(T_C\) , in resemblance to the behavior found for other Co- and Fe-based DPs containing three or more magnetic ions [1]}, [2]}, [3]}. In our case, for instance, the anomalies could be associated respectively to Co\(^{2+}\) —O—Ir\(^{4+}\)  and Fe\(^{3+}\) —O—Ir\(^{4+}\)  couplings, both predicted by the Goodenough-Kanamori-Anderson rules to be of AFM type. On the other hand, they could be related to the distinct magnetic orderings of roughly independent Co/Fe and Ir AFM sublattices, as recently suggested by DFT calculation in La\(_2\) CoIrO\(_6\)  [4]} and corroborated by XMCD and magnetization results in La\(_{2-x}\) Ca\(_x\) CoIrO\(_6\)  [5]}. Another very plausible scenario is the one in which there is only one magnetic transition and the second anomaly would be related to a crossover, i.e. some spin reorientation or structural change not necessarily associated with an order parameter.
